Sheet-feeding device



Aug. 10, 1965 J. MULLER SHEET-FEEDING DEVICE 5 Sheets-Sheet 1 Filed April 26, 1963 INVENTOR. JOSEF MULLER Jesfern, '20s: 6 Main! Aug. 10, 1965 J. MULLER SHEET-FEEDING DEVICE 5 Sheets-Sheet 2- Filed April 26, 1963 N Nam INVENTOR. J o s E F M U L L E R Jlesfem, Ross 6' JIaslzm Aug. 10, 1965 J. MULLER SHEET-FEEDING DEVICE 5 Sheets-Sheet 4 Filed April 26, 1963 INVENTOR.

JOSEF MULLER Aug. 10, 1965 J. MULLER 3,199,863

SHEET-FEEDING DEVICE Filed April 26, 1963 5 Sheets-Sheet 5 INVENTOR. JOSEF MULLER United States Patent 3,199,863 SHEET-FEEEENG DEVHIE Josef Miiiier, iostsirasse 2, Mouheim, Rhineiand, Germwy Filed Apr. 26, 1963, Ser. No. 275,830 Claims priority, application Germany, Apr. 28, 1962, M 52,679 13 Claims. (Cl. 271-26) The present invention relates to a device for the feeding of sheets from a stack.

Sheet-feeding devices of this type are used in supplying paper and other sheet material to a variety of receivers such as printing presses, distributing and collating apparatus or testing machinery. In every such instance it is necessary that only a single sheet be picked up at a time, this requirement being most satisfactorily met by devices using suction nozzles for lifting the top sheet off the stack. It has also been found advantageous to dispose a blower next to the stack for directing an air stream against the front edge of a sheet to be picked up, thereby facilitating separation of thetop sheet from the remainder of the stack and insuring that not more than one sheet at a time is removed. Conventional devices of this type are relatively bulky and expensive, owing in part to the fact that means had to be provided to maintain the level of the top sheet substantially constant upon the removal of successive sheets from the stack. This problem was usually solved by the provision of an elevatable stack support controlled by sheet feelers or the like to compensate for the progressive depletion of the stack.

The general object of the present invention is to provide an improved sheet-feeding device of the suctionoperated type which, while retaining all the advantages of this class of feeding machines, is considerably more compact and less complex than the known systems referred to so as to be comparable in cost and simplicity of operation to the cheaper but generally less reliable feeding devices of the type utilizing mechanical separating means (e.g. wheels or rollers) in place of suction.

A more particular object of this invention is to provide a sheet-feeding device of the character set forth in which a stack is deposited on a stationary support, thus dispensing with the need for providing means to raise a table or platform as the stack decreases in height.

The foregoing objects are realized in accordance with this invention by the provision of a vertically movable carrier for an array of suction nozzles above a stationary stack support, this carrier having attached to it a feeler disposed rearwardly of the suction nozzles and slightly below them so as to contact the top sheet of the stack, upon a lowering of the carrier, in a position in which the suction nozzles are still slightly spaced from the front edge of that sheet. When suction is applied, this front edge will be attracted upwardly as the sheet flexes away from the stack, it being of course necessary to synchronize the operation of the suction mechanism with the descent and subsequent ascent of the carrier. This vertical carrier motion is controlled by a driving mechanism comprising a positively reciproc-able element, preferably a swingable arm, which in the course of an opcrating cycle engages the carrier and lifts it in the course of a working stroke and subsequently, during a return stroke, allows the carrier to come down under its own weight (supplemented, if desired, by a suitable spring force or the like) until the feeler alights on the stack and stops the descent. At or just before that instant the suction mechanism becomes effective to pick up the front edge of the uppermost sheet; at the same time, advantageously, a blower synchronized with the suction mechanism directs a flow of air against the sheet edge, the

elevation of this blower being preferably controlled by another feeler to correspond substantially to the level of the top sheet regardless of the height of the stock.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is an overall side-elevational view of a sheetfeeding device according to the invention;

FIG. 2 is a front-elevational view of the device shown in FIG. 1;

FIG. 3 is a top plan view of the device;

FIGS. 4, 5 and 6 are side-elevational views of the upper part of the device of FIGS. 1-3, shown in different operating positions;

FIGS. 7 and 8 are side-elevational views of the lower part of the device, also shown in different operating positions;

FIG. 9 is a graph showing the correlating operations of the several units of the system of FIGS. 18; and

FIG. 10 is a side-elevational view illustrating a modification of the portions of the device shown in FIGS. 4-6.

Reference will first be made to FIGS. 1-9 in which there has been illustrated a device 10 for successively feeding a series of sheets from a stack 11 to a receiver, not shown, such as a printing press. Stack 11 is supported on a stationary table 12 which forms part of the fixed machine frame and constitutes the bottom of a boxlike holder for the stack including a rear wall 13 and side walls 14, 15. The box is open not only toward the top but also at the front where the side walls 14-, 15 have been foreshortened for a purpose that Will become apparent hereinafter; the fourth wall of the box is represented by an open grill 16.

A parallelogramm-atic linkage is defined by a vertical post 17, a pair of parallel rods 18, 19 and a vertical arm 26a of a generally upright elbow-shaped member 21? .also provided with a rearwardly and downwardly inclined arm 211 b; walls 13 and 19 are articulated to elements 17 and a, at the four corners of a parallelogram, by transverse rods 21, 22, 23 and 24. As shown in FIGS. 2 and 3, the linkages 17-20 are duplicated on opposite sides of the device and interconnected by the rods 2124. Each member 2% acts as a carrier for a suction head including an elongated horizontal manifold tube 25, here shown by way of example as being of square cross section, from which a plurality of suction nozzles 26 depend. A flexible conduit 27 leads to a source of partial vacuum, illustrated diagrammatically as the lowpressure port of a suction pump 23a; the high-pressure port of a compressor 28!) is connected via a flexible conduit 2 to the lower ends of two rigid pipes 30 which are vertically slidable on brackets 31, 32, carried by the grill 61, along the forward end of the stack 11. Pipes 30 support a manifold tube 33, generally similar to tube 25, which has a series of transversely spaced vents 34 for directing an air blast from compressor 28b through the interstices of grill 1% against the front edge of the top sheet of stack 11.

The mounting of manifold tube 25 on its carrier 21 includes a lug 35 on the arm 200, this lug being threadedly engaged by a supporting spindle 36 passing vertically through it. The upper end of each rod 36 (there being one for each member 20) terminates in a rotatable knob 37 while its lower end is received in a boss 38 rising from tube 25. A spacer bar is articulated, at each end of manifold tube 25, to that tube via a pin 40 and to the rear extremity of the corresponding arm 20b via a transverse rod 41; the lower face of this rod 41, which interconnects the carrier members 21) is the free ends of their arms 2%, lies somewhat below the level L of the undersides of nozzles 26. Knobs 37 serve for the adjustment of level L relative to the elevation of rod 41,

it being understood that the supporting spindles 36 are sufiiciently flexible and/or mounted with sufiicient play in their sockets 38 to allow for the slight lateral shifting of the suction head 25, 26 due to such adjustment.

If no horizontal feeding of the sheets from stack 12 were required, suction head 25, 26 would have to move only vertically and the posts 17 could be fixed on the machine frame relatively to table 12. In the embodiment illustrated, however, it is assumed that the sheets picked up by the suction head are to be moved forwardly for engagement by a feeding device, here symbolized by a pair of rollers 42, 43, which advances them toward their ultimate destination. For this purpose the posts 17, and with them the remaining elements 18, 19, 29 of the parallelographic linkages supporting the suction manifold 25, are shown to be horizontally displaeeable by being rigid with pistons 44 that are slidable in a pair of stationary hydraulic cylinders 45. Another hydraulic cylinder 46 has a piston 47 linked to a pair of control levers 43 which are pivoted at 49 to the respective posts 17; the free ends of levers 48 are interconnected by a bar 50 which in the normal position of the linkages, illustrated in FIG 1, bears from below upon the rods 18 to maintain the manifold 25 and its carrier 20 elevated, against the force of gravity and a supplemental spring 51, above the level L.

A further hydraulic cylinder 52 has its piston 53 articulated to a lever 54 which is pivoted at 55 to a depending boss 56 of table 12 and carries at its free end a transverse bar 57, it being understood that boss 56 and lever 54 are duplicated on opposite sides'of the machine in the manner illustrated in FIG. 3 for the analysis system 17, 48. Bar 57 normally bears from below upon a lever 58 which is pivoted at its midpoint on the fulcrum 55 and straddles with its bifurcated front end 53a a pin 59 on the associated pipe 30, the rear end 5812 of that lever carrying a transverse rod 6%) which at each end pivotally supports an internally threaded sleeve 61. A vertical spindle 62 threadedly engages the sleeve 61 and also passes through an unthreaded ring 63 bracketed between two collars 64, 65; ring 63 is pivoted on another transverse rod 66 which passes through the rear end of a lever 67. The lever 67, which as shown in FIG. 3 is duplicated on the opposite side of the stack 11, is pivoted at its midpoint on a pin 68 projecting from an upward extension 69 of table 12. The front ends of the two levers 67 are interconnected by a crossbar 7t) which in the normal position of FIG. 1 is spaced above the stack 11 under the control of bar 57. The position of bar 7t} can beadjusted with the aid of a knob 71 on spindle 62. The normal or starting position illustrated in FIGS i3 is represented by the time t in the graph of FIG. 9 which illustrates the correlated activation of cylinders 45, 46, 52, pump 28a and compressor 2812 under the control of a timer 72.

Reference will now be made to FIGS. 4-8 for a description of the operation of the device during a work cycle of timer 72.

In FIG. 4 the swingable arm 48 has been lowered into its bottom position (instant t FIG. 9) in which it has become disengaged from the rod 18 as the carrier extrernity 41 has come to rest on the top sheet of stack 11. It will be seen that in this position the nozzles 26 are still spaced above the level of stack 11 so that the top sheet 11a is aspirated upwardly as suction is applied during an interval t1Z to the manifold 25 by means of pump 28a. The operation of the suction head 25, 26, occurring as soon as or shortly before the system has reached the position shown in FIG. 4, thus lifts the front edge of sheet 11a oil the stack while the simultaneously emitted air stream from compressor 28b and blower head 33 loosens the upper sheets and separates the next-lower sheet from top sheet 11:: if it should accidentally adhere to the latter. It will be observed that, owing to the pressure bar 41, the sheets will not be blown off the stack; it will be seen from FIG. 9 that compressor 28]] is stopped at instant t thus just before gins to rise again under the control cylinder 46.

FIG. 5 shows the position of the linkage 17-2 at instant t when the stack ll. has been reduced to approximately half its original height. The position of arm 43 at the lower end of its stroke has not been changed but the links id, 19 and the carrier 2% have descended below their position of FIG. 4, with the nozzles 26 again spaced from the stack surface to attract the front edge of the top sheet 1112. FIG. 6 illustrates a further position in which only a single sheet Trio is left in the stack. With the relative position of nozzles 26 and bar 4} still unchanged, link 18 has come to rest on the cross-bar 54 of arm 48 which again occupies the same bottom position as in FIGS. 4 and 5. It will thus be apparent that the stroke of arm 48 is suflicient to allow for a vertical movement of carrier 2:) over a distance greater than the maximum height of the stack.

Concurrently with cylinder 4-6, i.e. in the interval t t as shown in FIG. 9, cylinder 52 has been operated by timer '72 to withdraw the cross-bar 5'7 from lever 58 so that blower head 33 is allowed to descend under its own weight (and/or, if desired, by a spring similar to that shown at 51) to align its vents 34- substantially with the top of stack 11. Because the ratios of the front and rear arms of levers 58 and 67 are alike, the vertical displacement of the pipes 39 will practically equal that of the bar 70 so that manifold 33 will always come to rest approximately at the level of the uppermost sheet of the stack. This has been illustrated in FIG. 7 which shows the stack 11 reduced to half its original height, as in FIG. 5, and in FIG. 8 which illustrates an extreme position corresponding to the situation shown in PEG. 6.

FIG. 9 shows that at the time when both the suction manifoidl Z5 and the blower manifold 35 have lecn restored to their normal positions illustrated in ES. 1, cylinder 45 is rendered operative to displace the piston 44 to the left whereby the top sheet 11a is entrained toward the rollers 42, 43, the suction pump 28a still being effective during this forward stroke. it instant t the pump 28a ceases to operate, the grip of nozzles 26 on sheet 11-11 is released and the cylinder 45 retracts the linkage i720 to its starting position above stack 11. This return movement occurs in the interval t;t whereupon the c cle is repeated.

In FIG. 10 there has been illustrated a modification of the means for raising and lowering the suction head 25, 26. In this embodiment each end of the manifold 25 and the corresponding spindle 36 are mounted on a carrier 12% whose vertical arm 12% is slotted at 12%, the inclined arm 12% having the same shape as the corresponding arm 2% in the preceding figures. A post 117, which may be stationary or horizontally displaceable as explained with reference to post 1'7, carries two studs 117a, 1375 which pass at vertically spaced locations through the slot 229a to guide the carrier 12% whereby the latter may be vertically reciprocated under the control of a swingable arm 148 with cross-bar 159 over a distance greater than the maximum b ht or" stack 11. The operation of this system is otherw e identical with that heretofore described.

What is claimed is:

1. A sheet-feeding device comprising a stationary support for a stack of sheets to be fed individually to a receiver therefor; a vertically movable carrier above said support; feeler means on said carrier adapted to be lowered upon the top sheet of a stack positioned on said support; suction means on said carrier disposed at a fixed distance above and forwardly of said feeler means for lifting a front edge of said top sheet off the remainder of the stack; drive means for reciprocating said carrier relatively to said support, said drive means including a reciprocable element with a vertical stroke length sufiicient to permit vertical displacement of said carrier over a the carrier 24') beof piston 47 and distance greater than the maximum height of said stack, said element being positively engageable with said carrier during a working stroke of said drive means for lifting said feeler means off said stack and disengageable therefrom for letting said feeler means come to rest on said stack upon a subsequent return stroke; and operating means synchronized with said drive means for actuating said suction means during said working stroke whereby said top sheet is pulled oil the stack.

2. A device as defined in claim 1 wherein said carrier is provided with adjusting means for varying the elevation of said suction means relative to said feeler means.

3. A device as defined in claim ll wherein said carrier comprises an elbow-shaped member with a vertical arm and a rearwardly and downwardly inclined arm rigid with said vertical arm, said feeler means being constituted by the free lower end of said inclined arm.

4. A device as defined in claim 3, further comprising a vertically adjustable holder for said suction means on said vertical arm.

5. A device as defined in claim 3, further comprising guide means for said member engaging said vertical arm at two vertically spaced locations.

6. A device as defined in claim 5 wherein said guide means comprises a post parallel to said vertical arm and a pair of parallel rods forming a parallelogrammatic linkage with said post and said vertical arm.

7. A device as defined in claim 6 wherein said swingable element is pivoted to said post between said parallel rods for operative engagement with the upper one of said rods.

8. A device as defined in claim 5 wherein said suction eans comprises a horizontal bar provided with a plurality of spaced-apart nozzles.

9. A device as defined in claim 8, further comprising lever means articulated to said bar and to said lower end of said inclined arm.

10. A device as defined in claim 1 wherein said drive means includes means for reciprocating said carrier forward and back in an elevated position of said suction means.

11. A sheet-feeding device comprising a stationary support for a stack of sheets to be fed individually to a re ceiver therefor; a vertically movable carrier above said support; feeler means on said carrier adapted to be lowered upon the top sheet of a stack positioned on said support; suction means on said carrier disposed at a fixed distance above and forwardly of said feeler means for lifting a front edge of said top sheet off the remainder of the stack; drive means for reciprocating said carrier relatively to said support, said drive means including a swingable element with a generally vertical sweep sufiicient to permit vertical displacement of said carrier over a distance greater than the maximum height of said stack, said element being positively engageable with said carrier during a worldng stroke of said drive means for lifting said feeler means ofif said stack and disengageable therefrom for letting said feeler means come to rest on said stack upon a subsequent return stroke; operating means synchronized with said drive means for actuating said suction means during said working stroke whereby said top sheet is pulled 0d the stack; and blower means synchro nized with said drive means for directing an air stream toward said front edge substantially concurrently with the operation of said suction means.

12. A device as defined in claim 11, further comprising a vertical grill interposed between said support and said blower means, said support having the form of a box open toward said grill, said blower means including a horizontal bar extending across the interstices of said grill.

13. A sheet-feeding device comprising a stationary support for a stack of sheets to be fed individually to a receiver therefor; a vertically movable carrier above said support, vertically movable blower means forwardly of said carrier trained upon said stack; first and second feeler means adapted to be lowered upon the top sheet of a stack positioned on said support, said first feeler means being mounted on said carrier, said second feeler means being mechanically linked with said blower means; suction means on said carrier disposed in a predetermined position relative to said first feeler means above and forwardly of the latter for lifting a front edge of said top sheet or": the remainder of the stack; drive means for reciprocating said carrier and said blower means relatively to said support, said drive means including a first and a second reciprocable element each with a generally vertical stroke length sufficient to permit vertical displacement of said carrier and said blower means over a dis tance greater than the maximum height of said stack, said elements being positively engageable with said carrier and with said blower means, respectively, during a working stroke of said drive means for lifting said first and second feeler means off said stack and disengageable therefrom for letting said first and second feeler means come to rest on said stack upon a subsequent return stroke, said blower means being so coupled with said second feeler means as to be held substantially at the level of said top sheet in the rest position of said second feeler means; first operating means synchronized with said drive means for actuating said suction means during said working stroke whereby said top sheet is pulled olf the stack; and second operating means synchronized with said drive means for actuating said blower means substantially concurrently with said suction means to direct an air stream toward said front edge.

14. A device as defined in claim 13 wherein said second feeler means comprises a first lever fulcrumed on said support, said first lever having a sheet-engaging front end disposed rearwardly of said first feeler means, a second lever longer than said first lever fulcrumed on said support, said blower means being provided with a substantially vertical mounting member articulated to the front end of said second lever, and a link parallel to said mounting member articulatedly interconnecting the rear ends of said levers.

15. A device as defined in claim 14 wherein said link is of adjustable length.

16. A device as defined in claim 14 wherein said second lever extends below said support, said second swingable element being pivoted to said support for operative engagement with said second lever.

17. A device as defined in claim 13, further comprising spring means biasing at least one of said elements in a downward direction.

18. A device as defined in claim 13 wherein each of said elements comprises a swingable lever arm.

References Cited by the Examiner UNITED STATES PATENTS 1,089,274 3/ 14 Von Sazenhofen. 1,304,262 5/19 Christophel 271-27 1,480,012 1/24 Roden 27127 1,625,085 4/27 Leach 271-27 2,488,767 11/49 Drott et al. 214-147 FOREIGN PATENTS 657,827 3/38 Germany.

HUGO O. SCHULZ, Primary Examiner. 

1. A SHEET-FEEDING DEVICE COMPRISING A STATIONARY SUPPORT FOR A STACK OF SHEETS TO BE FED INDIVIDUALLY TO A RECEIVER THEREFOR; A VERTICALLY MOVABLE CARRIER ABOVE SAID SUPPORT; FEELER MEANS ON SAID CARRIER ADAPTED TOI BE LOWERED UPON THE TOP SHEET OF A STACK POSITIONED ON SAID SUPPORT; SUCTIN MEANS ON SAID CARRIER DISPOSED AT A FIXED DISTANCE ABOVE AND FORWARDLY OF SAID FEELER MEANS FOR LIFTING A FRONT EDGE OF SAID TOP SHEET OFF THE REMAINDER FO THE STACK; DRIVE MEANS FOR RECIPROCATING SAID CARRIER RELATIVELY TO SAID SUPPORT, SAID DRIVE MEANS INCLUDING A RECISPROCABLE ELEMENT WITH A VERTICAL STROKE LENGTH SUFFICIENT DISTANCE GREATER THAN THE MAXIMUM HEIGHT OF SAID STACK, DISTANCE GREATER THAN THE MAXIMUM HEIGHT OF SAID STACK, SAID ELEMENT BEING POSITIVELY ENGAGEABLE WITH SAID CARRIER DURING A WORKING STROKE OF SAID DRIVE MEANS FOR LIFTING SAID FEELER MEANS OFF SAID STACK AND DISENGAGEABLE THEREFROM FOR LETTING SAID FEELER MEANS COME TO REST ON SAID STACK UPON A SUBSEQUENT RETURN STROKE; AND OPERATING MEANS SYNCHRONIZED WITH SAID DRIVE MEANS FOR ACTUATING SAID SUCTION MEANS DURING SAID WORKING STROKE WHEREBY SAID TOP SHEET IS PULLED OFF THE STACK. 